Thread cutting mechanism for looms



R. G. TURNER 2,305,287

THREAD CUTTING MECHANISM FOR LOOMS Filed April 15, 1942 j fi? INVEN-roRRlcl-mnb G=TuRNER ATTORNEY Patented Dec. 22, 1942 UNITED STAT S FTETOFFICE THREAD CUTTING MECHANISM FOR LOOMS Application April 13, 1942,Serial No. 438,780

9 Claims.

This invention relates to improvements in weft thread cutters for loomsand it is the general object of the invention to provide two cuttingedges, one on the shuttle behind the thread and the other in front ofthe thread, to be operated by forward motion of the shuttle.

At the time of weft replenishment a thread extends from the depletedbobbin through the shuttle delivery eye and along the front shuttle wallto the adjacent selvage. It is desirable to cut this thread as near thedelivery eye as possible so that the outgoing depleted bobbin willunthread the delivery eye. This general result is accomplished by themechanism set forth in prior Patent No. 1,881,920 wherein the frontshuttle wall is provided with a smooth plate across which the threadextends and in position to cooperate with a cutting edge mounted infront of the lay. It is an important object of my present invention toprovide the cutting plate with a series of cutting edges along which thecutter slides to cut the thread as the lay approaches front center onreplenishing beats of the loom.

It is another object of my present invention to provide the front wallof the shuttle with a plate having diagonal spaced cutting edges formedon ribs the top surfaces of which are beveled to insure contact betweenthe diagonal cuttin edges and the cutter blade.

It is a more specific feature of my invention to provide cuttingmechanism of the type already described wherein the angle of thediagonal cutting edges bears such a relation to the height of the threadcutter that the latter engages only two of the diagonal ridges at a timefor the pur pose of allowing the thread cutter to adjust itself on itspivot with respect to the plane determined by the two edges which itengages.

With these and other objects in view which will appear as thedescription proceeds, my invention resides in the combination andarrangement of parts hereinafter described and set forth.

In the accompanying drawing, where three forms of my invention are setforth,

Fig. 1 is a front elevation of a shuttle and thread cutter madeaccording to the preferred form of my present invention, together withcer tain adjacent mechanism,

Fig. 2 is a horizontal sect-ion on line 2-2 of Fig. 1,

Fig. 3 is an enlarged horizontal section similar to a part of Fig. 2,

Fig. 4 is an enlarged vertical section on line 4-4 of Fig. 2,

Fig. 5 is a diagrammatic front elevation on an enlarged scale of theplate and cutter blade shown in Fig. 1,

Fig. 6 is a view similar to Fig. 1 but showing the first modification ofmy invention wherein the shuttle carried'cutting edges are vertical,

Fig. '7 is a view similar to Fig. 2 but showing the second modificationof my invention wherein the single cutter is on the shuttle,

Fig. 8 is a front elevation of the shuttle carried cutter shown in Fig.'7, and

Fig. 9 is a rear elevation of the front cutter shown in Fig. 7.

Referring particularly to Figs. 1 and 2, I have shown a loom lay Lprovided with a shuttle box B to receive a shuttle S containing a weftbobbin W; The right end of the shuttle as shown in Fig. 2 is providedwith athread passage HI leading to a delivery eye l the forward end ofwhich preferably communicates with the groove l2 extendinglongitudinally along the front wall I3 of the shuttle. The groove is notnecessary but does assist in proper tensioning of the weft thread. Asthe weft thread T is unwound from the bobbin it extends through thepassage Ill, through the delivery eye II, and then leads to the left forattachment to the adjacent selvage. It is to be understood that theshuttle box shown in Figs. 1 and 2 is located at the right hand end ofthe loom and will be provided with a shuttle binder l5.

An arm 20 is pivoted as at 2| on a fixed support 22 and is normallyurged rearwardly by a torsion spring 23 as indicated in Fig. 2. Thelever 2!] ordinarily has the right end thereof held in forward positionby engagement of its left end by a part 24 of the transfer mechanism ofthe loom not shown. On a replenishing beat the part 24 moves forwardlyto allow the spring 23 to move the right end of lever 20 rearwardly fromits normal position. A cutter blade 25 having a cutting edge 26 ispivoted as at 2'! to a stem 28 held in angularly adjusted position inbearing 29 on lever 20 by set screw 30. Cutting edge 26 is located tothe rear of pivot 2| so that it moves to the right when moved forwardlyby the advancing shuttle.

The matter thus far described, except for the forms of the cuttingmechanism to be described hereinafter, may be the same as that set forthin the previously mentioned patent. Under normal conditions the lay Lmoves back and forth in the loom and the transfer mechanism not shownholds the lever in forward position with the cutter blade in non-cuttingposition. On replenishing beats of the loom, however, lever 20 swingsrearwardly to project the cutting edge 26 into the path of the advancingshuttle and the latter engages blade to move it forwardly and also tothe right.

In carrying the preferred form of my present invention into effect Iprovide the front wall l3 of shuttle S with a plate 33 having a seriesof diagonal cutting ribs or ridges separated by grooves 36. The tops ofthe ribs are flat and each has a cutting edge 31 at the left hand sidethereof as viewed in Fig. 5. The forward surfaces of the ribs may beground to provide the cutting edges 31 a single grinding operation inwhich case the surfaces 40 lie in a plane.

In operation, the thread T extends across the plate 33 to have contactat spaced intervals with the ribs. So long as there is suificient weftfor continued weaving the cutter blade 25 is in forward position withits edge 26 vertical in the preferred form, but when a replenishingoperation occurs the blade will be moved rearwardly so that its cuttingedge 26 will occupy some such position as that indicated by the singleline 26 in Fig. 5. As the shuttle moves forwardly it will cause the ribs35 and thread to move against the cutting edge 26. During subsequentadvance of the shuttle the cutter 25 will slide along the ribs to theright, Figs. 2 and 5, to assume some such position as 26a in Fig. 5. Thesweep of the blade along the plate is sufficient to cause the thread Tto be cut by the cutting edge 26 by at least one of the ribs whether thethread be engaged by the upper or the lower part of the cutting edge 26.

In the first modification shown in Fig. 6 I provide the shuttle with aplate having vertical ribs 46 the left edges of which have cutting edges41. The top surfaces 48 of ribs 46 are beveled, being inclinedrearwardly in the direction in which the cutter 25 moves during thecutting operation. In this form of the invention the stem 28 is turnedin bearing 29 so that the cutting edge 26 is oblique to a vertical line,thus assuming a diagonal relation with respect to the vertical cuttingedges 41. It will be noted that as the thread passes from the deliveryeye to the left it approaches the lower edges 49 of the inclinedsurfaces 48 and leaves the cutting edges 41.

Because of this relation of the direction of inclination of the surfaces48 with respect to the direction in which the weft thread moves there islittle likelihood that the ribs 46 will cut the thread. I find in factthat there is very little likelihood that the thread will be cut whenthe tops of the ribs are made asin the preferred form of the invention.

' In the second modification the single cutting edge is on the shuttlewhile the cutting ribs are on stem 28. As shown in Fig. 8 the shuttle Shas a plate 56 on its front wall, and a single cutter blade 5| with acutting edge 52 extends diagonally across the plate. The cutter 25 isreplaced by a cutter head or member 55 pivoted to stem 28 and having aseries of spaced vertical ribs 56 with cutting edges 51, as shown inFig. 9. The ribs 56 need not necessarily be vertical nor blade 5|oblique, so long as the diagonal relation suggested in the first twoforms of the invention is preserved.

The action of these modifications is similar to that described for thepreferred form. In each form a single blade has sliding engagement with"a set of cutting edges diagonal to it to cut the thread leading fromthe shuttle. In practice it is probable that only one of the series ofribs cooperates with the single cutter in the actual cutting of thethread, but the shuttle is subject to slight variations in its positionand for this reason it is desirable that a series of ribs be used towiden the range of operation of the cutting mechanism.

A refinement of my invention concerns the relationship between theheight of the cutting edge 26 and the angle of inclination of the ribstogether with their spacing. This relationship may exist for all formsof the invention, but I will describe it in connection with Fig. 5,where it will be seen that when the lower part of the cutting edge 26engages one of the ribs its upper end will engage the next rib to theright, but will not engage a third rib. As the cutting edge 26 assumessuccessive positions to the right it will move entirely clear of thefirst rib before engaging another rib. The result of this relationshipis that the cutting edge 26 has engagement with but two ribs at a timeand if adjacent cutting edges on the plate should not be exactlyparallel, the blade 25 can adjust itself to move into the planedetermined by the cutting edges which it engages, due to pivotalconnection 21. While the relationship just described is desirable I havefound in actual practice that the cutter will operate satisfactorily ifthe blade 25 engages three ribs at a time.

From the foregoing it will be seen that I have provided a simple form ofweft thread cutting mechanism wherein two cutting edges diagonallydisposed to each other cooperate to cut the thread near the shuttledelivery eye. Experience shows that the type of plate set forth hereinwill cut threads of large diameter such as are not always satisfactorilycut when the plate has a flat surface as set forth in the prior art. Itwill also be seen that if desired, the relation between the height ofthe single cutting edge, the angle of the ribs, and their lateralspacing, can be such that the cutting part on stem 28 will never engagemore than two ribs at a time and can therefore adjust itself to lie inthe plane of two adjacent cutting edges on the cooperating plate. Asstated hereinbefore, however, this is not an essential feature. It willalso be noted that the top surfaces of the ribs can be inclined toimprove the cutting operation and that the direction of inclination issuch as to minimize risk of cutting the thread.

Having thus described my invention it will be seen that changes andmodifications may be made therein by those skilled in the art withoutdeparting from'the spirit and scope of the invention and I do not wishto be limited to the details herein disclosed, but what I claim is:

1. In thread parting mechanism for a loom having a lay and a shuttlemovable forwardly with the lay, means on the shuttle defining a cuttingedge across which the weft thread from the shuttle extends, and a weftparter operated by forward motion of the shuttle and having a cuttingedge diagonal with respect to the cutting edge on the shuttle to slidealong the latter in contact therewith to part the weft thread.

2. In loom thread parting mechanism having two cooperating threadcutters one of which is on a shuttle behind the shuttle weft thread andone of which is mounted in front of the thread, one of said cutterscomprising a series of spaced cutting edges to cooperate with thecutting edge of the other cutter, and means operated by forward motionof the shuttle to cause the cutting edge of the other cutter to engagethe elements successively during th thread parting operation to part thethread.

3. In thread parting mechanism for a 100m operating with a shuttlehaving a thread extending therefrom, two cooperating cutting members oneof which is on the shuttle behind the thread and one of which is infront of the thread, means to mount one of said members so that thecutting edge thereof is diagonal with respect to the cutting edge of theother member, and means operated by forward motion of the shuttle tocause a point of engagement between the cutting edges of said members tomove along said edges during a thread parting operation to part thethread.

4. In loom thread parting mechanism having two cutter members one ofwhich is on a shuttle behind the weft thread and one of which is infront of the thread and wherein forward motion of the shuttle causes thecutter members to move in sliding engagement with each other with thethread between them to part the thread, one of said cutters comprising aseries of spaced cutting edges and the other cutter having a cuttingedge which is diagonal to said cutting edges as the cutters move withrespect to each other during the thread parting operation.

5. In loom thread parting mechanism having two cooperating threadcutters one of which is on a shuttle behind the thread and one of whichis in front of the thread and wherein forward motion of the shuttlecauses relative sliding engagement of the cutters during a threadparting operation with the thread between them, one of said cutterscomprising a series of spaced cutting edges extending transversely ofthe thread at a given angle with respect to the thread and the othercutter having a cutting edge also extending transversely of the threadbut at a different angle with respect to the thread to have progressiveengagement with the cutting edges of said series as said cutters haverelative sliding engagement.

6. In thread parting mechanism for a 100m operating with a shuttlehaving a thread extending therefrom, two cooperating cutter members,

one on the shuttle behind the thread and the other in front of thethread, one of said members having a series of spaced thread cuttingedges, the other cutter having a cutting edge to cooperate with saidseries of cutting edges, and means operated by forward motion of theshuttle to cause the cutting edge of said other cutter to haveprogressive sliding engagement with the cutting edges of said series ina direction diagonal to the latter to part the thread.

7. In thread parting mechanism for a loom operating with a shuttlehaving a thread delivery eye, means on the shuttle to provide a seriesof spaced cutting edges behind and extending transversely of the thread,a cutter in front of the thread having a cutting edge to cooperate withcutting edges on the shuttle, and means operated by forward motion ofthe shuttle to cause the cutting edge of said cutter to slide across thecutting edges on the shuttle to engage said edges progressively and partthe thread.

8. In loom thread parting mechanism comprising a plate on a shuttlebehind the thread extending from the shuttle, a series of thread cuttingribs on said plate across which the thread extends, a cutter in front ofsaid plate having a cutting edge diagonal with respect to said ribs, andmeans operated by forward motion of the shuttle to move the said cutteracross said ribs and maintain the cutting edge of said cutter diagonalwith respect to said ribs during the thread parting operation.

9. In loom thread parting mechanism comprising two cooperating cuttermembers one of which is mounted on a shuttle behind the weft threadextending from a delivery eye of the shuttle and one of which is infront of the thread, one of said cutter members comprising a series ofspaced cutting elements and the other cutting member having a cuttingedge diagonal with respect to said elements, and means to move saidmember relatively and in engagement with each other in a directionoblique to said elements to part the thread, said cutting edge andcutting elements being so related that said cutting edge engages but twoelements at a time.

RICHARD G. TURNER.

